¶ Here he puttes þe 5 case, þe quych is leaf 151 a. *þis: If the second figure is one, put a cipher, and write five over the next figure. yf þe secunde figure be of 1, as þis is here 12, þou schalt do away þat 1 & sett þere a cifer. & sett 5 ouer þe next figure hede afore toward þe riȝt side, as þou diddyst afore; & þat 5 schal be [haldel] of þat 1, þe quych 1 is rekent for 10. lo an Ensampulle, 214. medye 4. þat schalle be 2. do away 4 & sett þere 2. þen go forth to þe next figure. þe quych is bot 1. do away þat 1. & sett þere a cifer. & set 5 vpon þe figures hed afore, þe quych is nowe 2, & þen þou schalt haue þis nombre 5
202, þen worch forth to þe [nex] figure. And also it is no [maystery] yf þere come no figure after þat on is medyet, þou schalt write no 0. ne nowȝt ellis, but set 5 ouer þe next figure afore toward þe ryȝt, as þus 14. How to halve fourteen. medie 4 then leues 2, do away 4 & sett þere 2. þen medie 1. þe quich is rekende for ten, þe haluendel þere-of wel be 5. sett þat 5 vpon þe hede of þat figure, þe quych is now 2, 5
2, & do away þat 1, & þou schalt haue þis nombre yf þou worch wel, vnde versus.
How to prove the Mediation.
¶ Si mediacio sit bene facta probare valebis
¶ Duplando numerum quem primo dimediasti
How to prove your mediation. ¶ Here he telles þe how þou schalt know wheþer þou hase wel ydo or no. doubul leaf 151 b. *þe nombre þe quych þou hase mediet, and yf þou haue wel y-medyt after þe dupleacioɳ, þou schalt haue þe same nombre þat þou haddyst in þe tabulle or þou began to medye, as þus. First example. ¶ The furst ensampulle was þis. 4. þe quych [I-mediet] was [laft] 2, þe whych 2 was write in þe place þat 4 was write afore. Now doubulle þat 2, & þou schal haue 4, as þou hadyst afore. The second. þe secunde Ensampulle was þis, 245. When þou haddyst mediet alle þis nombre, yf þou haue wel ydo þou schalt haue of þat mediacioɳ þis nombre, 122w. Now doubulle þis nombre, & begyn in þe lyft side; doubulle 1, þat schal be 2. do away þat 1 & sett þere 2. þen doubulle þat oþer 2 & sett þere 4, þen doubulle þat oþer 2, & þat wel be 4. þen doubul þat merke þat stondes for halue on. & þat schalle be 1. Cast þat on to 4, & it schalle be 5. do away þat 2 & þat merke, & sette þere 5, & þen þou schal haue þis nombre 245. & þis wos þe same nombur þat þou haddyst or þou began to medye, as þou mayst se yf þou take hede. The third example. The nombre þe quych þou haddist for an Ensampul in þe 3 case of mediacioɳ to be mediet was þis 241. whan þou haddist medied alle þis nombur truly leaf 152 a. *by euery figure, þou schall haue be þat mediacioɳ þis nombur 120w. Now dowbul þis nombur, & begyn in þe lyft side, as I tolde þe in þe Craft of duplacioɳ. þus doubulle þe figure of 1, þat wel be 2. do away þat 1 & sett þere 2, þen doubul þe next figure afore, the quych is 2, & þat wel be 4; do away 2 & set þere 4. þen doubul þe cifer, & þat wel be noȝt, for a 0 is noȝt. And twyes noȝt is but noȝt. þerefore doubul the merke aboue þe cifers hede, þe quych betokenes þe haluendel of 1, & þat schal be 1. do away þe cifer & þe merke, & sett þere 1, & þen þou schalt haue þis nombur 241. And þis same nombur þou haddyst afore or þou began to medy, [& yf] þou take gode hede. The fourth example. ¶ The next ensampul þat had in þe 4 case of mediacioɳ was þis 4678. Whan þou hast truly [ymedit] alle þis nombur fro þe begynnynge to þe endynge, þou schalt haue of þe mediacioɳ þis nombur 5
2334. Now doubul this nombur & begyn in þe lyft side, & doubulle 2 þat schal be 4. do away 2 and sette þere 4; þen doubule 3, þat wol be 6; do away 3 & sett þere 6, þen doubul þat oþer 3, & þat wel be 6; do away 3 & set þere leaf 152 b. *6, þen doubul þe 4, þat welle be 8; þen doubul 5. þe quych stondes ouer þe hed of 4, & þat wol be 10; cast 10 to 8, & þat schal be 18; do away 4 & þat 5, & sett þere 8, & sett that 1, þe quych is an articul of þe Composit þe quych is 18, ouer þe next figures hed toward þe lyft side, þe quych is 6. drav þat 1 to 6, þe quych 1 in þe dravyng schal be rekente bot for 1, & þat 1 & þat 6 togedur wel be 7. do away þat 6 & þat 1. the quych stondes ouer his hede, & sett ther 7, & þen þou schalt haue þis nombur 4678. And þis same nombur þou hadyst or þou began to medye, as þou mayst see in þe secunde Ensampul þat þou had in þe 4 case of mediacioɳ, þat was þis: The fifth example. when þou had mediet truly alle the nombur, a principio usque ad finem. þou schalt haue of þat mediacioɳ þis nombur 5
102. Now doubul 1. þat wel be 2. do away 1 & sett þere 2. þen doubul 0. þat will be noȝt. þerefore take þe 5, þe quych stondes ouer þe next figures hed, & doubul it, & þat wol be 10. do away þe 0 þat stondes betwene þe two figuris, & sette þere in his stid 1, for þat 1 now schal stonde in þe secunde place, where he schal betoken 10; þen doubul 2, þat wol be 4. do away 2 & sett þere 4. & leaf 153 a. *þou schal haue [þus] nombur 214. þis is þe same numbur þat þou hadyst or þou began to medye, as þou may see. And so do euer more, yf þou wil knowe wheþer þou hase wel ymedyt or no. ¶. doubulle þe numbur þat comes after þe mediaciouɳ, & þou schal haue þe same nombur þat þou hadyst or þou began to medye, yf þou haue welle ydo. or els doute þe noȝt, but yf þou haue þe same, þou hase faylide in þi Craft.
The Craft of Multiplication.
Sequitur de multiplicatione.
To write down a Multiplication Sum.
S i tu per numerum numerum vis multiplicare
Scribe duas quascunque velis series numerorum